Hard disk drives are common information storage devices. FIG. 1a provides an illustration of a typical disk drive unit 100 essentially consisting of a series of rotatable disks 101 mounted on a spindle motor 102, and a Head Stack Assembly (HSA) 130 which is rotatable about an actuator arm axis 105 for accessing data tracks on disks during seeking. The HSA 130 includes at least one drive arm 104 a head gimbal assembly (HGA) 150. Typically, a spindling voice-coil motor (VCM) is provided for controlling the motion of the drive arm 104.
Referring to FIG. 1b, the HGA 150 includes a thermally assisted head 110 having a slider 103, and a suspension 190 to load or suspend the slider 103 thereon. The suspension 190 includes a load beam 106, a base plate 108, a hinge 107 and a flexure 109, all of which are assembled together. A write transducer and a read transducer (not shown) are embedded in the pole tip of the slider 103 for writing and reading data. When the disk drive is on, a spindle motor 102 will rotate the disk 101 at a high speed, and the slider 103 will fly above the disk 101 due to the air pressure drawn by the rotated disk 101. The slider 103 moves across the surface of the disk 101 in the radius direction under the control of the VCM. With a different track, the slider 103 can read data from or write data to the disk 101.
This thermally assisted head 110 applies a thermal energy source, such as a laser diode at or near the location of the write transducer. This thermal energy source provides energy to the recording medium, which reduces the medium's coercivity to facilitate the writing process. Thus, this thermally assisted head 110 including a laser diode chip become more and more desirable.
Generally, the conventional thermally assisted head with the conventional laser diode chip is made by the following steps, as shown in FIG. 1c. 
Step (1001), providing a laser diode bar;
Step (1002), coating an antireflection coating on the laser diode bar;
Step (1003), cutting the laser diode bar into several individual laser diode chips by a scribe device; concretely, forming a groove on the laser diode bar by a blade or a laser beam, and then dividing into individual laser diode chips along the groove.
Step (1004), bonding the laser diode chip on a substrate mount to form a laser diode module;
Step (1005), bonding the laser diode module on a slider to form thermally assisted head.
However, the laser diode module made by the conventional method has several problems on the sequent machining processes which commonly include cleaning process, press process and transfer process and the like. As the blade or laser beam cuts the laser diode bar directly, thus the cutting edge of the laser diode chip is rough, which may increase the possibility of the antireflection coating de-bonding from the laser diode chip. Worse still, the antireflection coating on the laser diode chip will peel off from the laser diode chip body during the cleaning process by brush or by ultrasonic. Moreover, the laser diode chip even will generate some cracks on its surface under the action of some stress during the press process. Therefore, the performances of the laser diode chip and the thermally assisted head are weakened which are undesired by the manufacturer and the consumer.
Accordingly, it is desired to provide improved manufacturing methods of a thermally assisted head and a light source chip, so as to obtain an improved thermally assisted head and light source chip to overcome the above-mentioned drawbacks.